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Anatomical Landmarks,Physiology And
MyologyOf Facial
Expression
Done By: Mohammed AbdulazizSupervised By: Dr Faiza M AbdulAmeer
Contents… Introduction Extra-Oral Anatomical Landmarks Intra-Oral Anatomical Landmarks
-Classification Of Oral Mucosa-Landmarks Of Maxillary Edentulous Arch-Landmarks of Mandibular Edentulous Arch
Myology Of Face And Oral Cavity Physiology Of Oral Cavity Conclusion
Introduction…
The good knowledge of anatomy and physiology is a keystone in getting the best result during the fabrication of any prosthesis, this best result is which restores the missing oral parts and preserves what is remaining.
Facial Anatomical Landmarks
Effects Of Edentulism on face:1-2-
Eye
Ear
Nose
Lips
Folds (Grooves)
Naso Labial Angel
Indication of lip support by upper anterior teeth.
Used In jaw-relation clinic to correct the position of wax rim anteriorly
90-110 in average.
Interpupillary line + Ala Tragus Line
Canthus Tragus Line
13 mm
Oral Mucosa
Epithelial Layer
Connective Tissue layer
Sub-Mucosa
Types Of Oral Mucosa
Masticatory Mucosa
Lining MucosaSpecialized Mucosa
Masticatory Mucosa
Free, attached gingiva and hard palate comes in primary contact with food during mastication and is keratinized.
Lining Mucosa
the lips cheeks, vestibule, floor of the mouth, ventral surface of the tongue and soft palate. It does not function in mastication. It is soft, pliable and non-keratinized.
Specialized Mucosa
SPECIALIZED MUCOSA: on the dorsal surface (dorsum) of the tongue. It is covered with cornified epithelial papillae.
Intra Oral Anatomical Landmarks
Maxillary Anatomical LandmarksMandibular Anatomical
Landmarks
Maxillary Anatomical Landmarks
a} Limiting structures
- Labial frenum
- Labial vestibule
- Buccal frenum
- Buccal vestibule
- Hamular notch
- Posterior palatal seal area
b} Supporting structures-Hard palate -Residual ridge -Palatal rugaeMaxillary Tuberosity
c} Relief areas- Incisive papilla- Mid palatine raphe- Canine Eminence- Fovea palatine - Palatal Tori
Limiting StructuresLabial Frenum It contains no muscle and has
no action on its own. It should be properly relieved.
Limiting StructuresLabial Vestibule The labial vestibule is divided
into a left and right labial vestibule by the labial frenum and extends upto the buccal frenum on either side.
The main muscle of the lip, which forms the outer surface of the labial vestibule, is the orbicularis oris.
Limiting StructuresBuccal Frenum Consist of one or more bands. Influenced by 3 muscles
Orbicularis oris (forward) Buccinator (backward) Levator anguli oris (position)
Limiting StructuresBuccal Vestibule Buccal frenum to hamular
notch
Limiting StructuresHamular Notch Situated between the
tuberosity and hamulus of the medial pterygoid plate.
Distal extension of denture. If the denture extends too far
into the hamular notch, the mucous membrane covering the raphe will be traumatized.
Anterior Vs Posterior Vibrating lines
Limiting StructuresPosterior Palatal Seal Area The soft tissue area at or
beyond the junction of the hard and soft palates on which pressure,within physiologic limits, can be applied by a denture to aid in its retention”. (GPT-8).
Posterior palatal seal has several advantages.
Supporting StructuresHard Palate The horizontal part of palate is
considered as primary stress bearing area.
Supporting StructuresResidual Ridge “The portion of the alveolar
ridge and its soft tissue covering, which remains following the removal of teeth”.(GPT-8).
Supporting StructuresPalatal Rugae This area contributes to the
stress-bearing role (secondary stress bearing area) as well as to retention although in a secondary capacity.
Supporting StructuresMaxillary tuberosity It is considered as secondary
stress bearing area, if it is firm it can withstand more forces.
Sometimes it is oversized either with soft tissue or with bone.
Combination Syndrome
Relief areasIncisive Papilla This covers the incisive
foramen and is located in the midline immediately behind and between central incisors.
Care should be taken that the denture base does not impinge on them and hence should be relieved.
Relief areasMid Palatine Raphe Adequate relief should be
provided in this area as, mucosa covering the raphe is extremely thin and is traumatized easily.
Relief areasCanine Eminence
Relief areasFovea Palatine
Relief areasPalatal Tori
Mandibular Anatomical Landmarks
Limiting structures
- Labial frenum-Labial vestibule -Buccal frenum-Buccal vestibule-Lingual frenum-Alveololingual sulcus-Retromolar pad
Supporting structures-buccal shelf area.-residual alveolar ridge.
Relief areas
-mental foramen.
-genial tubercle.
-Mylohyoid ridge.
-Torus mandibularis.
Limiting StructuresLabial Frenum
Limiting StructuresLabial Vestibule
Limiting StructuresBuccal Frenum
Limiting StructuresBuccal Vestibule
Limiting StructuresLingual Frenum
Limiting StructuresAlveololingual sulcus
Limiting StructuresRetromolar Pad
Supporting StructuresBuccal Shelf Area It is considered as primary
stress bearing area. It is horizontal and made up of
dense cortical bone.
Supporting StructuresResidual Alveolar Ridge It is considered as secondary
stress bearing area (lateral slopes).
The crest of the ridge should be relieved.
Relief AreasMental Foramen
Relief AreasGenial Tubercle
Relief AreasMylohyoid Ridge Soft tissue usually hides the
sharpness of mylohyoid ridge. The mucous membrane
overlying the sharp or irregular mylohyoid ridge needs to be relieved.
Relief AreasTorus Mandibularis
Is it time for restAny energy remained
Myology Of Face And Oral Cavity -Physiology Of Muscles -Muscles Of Facial
Expression -Sopra-Hyoid Muscles -Infra-Hyoid Muscles -Muscles Of Mastication -Muscles Of The Tongue -Muscles O Soft-Palate
Muscles Of Facial Expression
Modiolus
Modiolus
Muscles Of Facial ExpressionBuccinator Is a thin quadrilateral muscle,
occupying the interval between the maxilla and the mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.
Muscles Of Facial ExpressionBuccinator
Muscles Of Facial ExpressionOrbicularis Oris “The orbicularis oris muscle is a
complex of muscles in the lips that encircles the mouth. Until recently, it was misinterpreted as a sphincter, or circular muscle, but it is actually composed of four independent quadrants that interlace and give only an appearance of circularity.”
Saladin, "Anatomy & Physiology: The Unity of Form and Function". 5th edition. McGraw Hill. Page 330
Muscles Of Facial ExpressionMentalis Muscle When contracts it can dislodge
the denture. It dictates the level of
extension of the labial flange of mandibular denture.
Reduce the lower labial vestibule when it contracts.
Supra-Hyoid Muscles
Act in elevating the hyoid bone and larynx and depression of the mandible.
The mylohyiod and geniohyiod may influence border of mandibular denture.
The mylohyoid constitutes the floor of the mouth.
Infra-Hyoid Muscles
actions of these muscles are important to the prosthodontist, for they are a part of the kinetic chain of the mandibular movement.
Muscles Of Mastication
These muscles have masticatory and non-masticatory movements, but in concern of complete denture, the non-masticatory movements have more influence on denture borders. Also these muscles especially the temporalis aid in obtaining centric relation.
Muscles Of MasticationTemporalis Muscle ACTIONS OF TEMPORALIS - Elevates the mandible, this
movement requires both the upward pull of anterior fibers and backward pull of the posterior fibers.
- Posterior fibers draw the mandible backwards after it has been protruded.
Muscles Of MasticationMasseter Muscle
ACTIONS OF MASSETER: Elevates the mandible to close
the mouth and to occlude the teeth in mastication.
It has a small effect in side-to- side movement, protraction and retraction.
Muscles Of MasticationMedial And Lateral Pterygoids The fibers of the lateral
pterygoid, pull the mandible forwards (protrusion) and medially.
The fibers of the medial pterygoid also perform the same actions in addition elevate the mandible.
Muscles Of The Tongue
Intrinsic muscles Extrinsic muscles
Styloglossus Palatoglossus Genioglossus hyoglossus
Importance of Tongue In Prosthodontics After loss of teeth, tongue
expands into the space created by lost teeth, this enlargement make the impression more difficult, and reduce the stability of denture.
The level of occlusal table in relation to tongue level is so important because high occlusal level reduces the retention of denture, while low occlusal level contributes in tongue biting during function.
Muscles Of Soft Palate
1. Tensor veli palatini : It influences the denture border in the hamular notch
2. Levator veli palatini: it helps in determining the vibrating line.
3. Palatoglossus: it exerts pressure on the lingual extension of the lower denture mainly when the tongue is moved toward the cheek.
4. Palatopharyngeous 5. The uvula: is unpaired
Classification of soft palate: House’s classification
Class I: the soft palate is almost horizontal curving gently downwards
Class II: the soft palate turns downward at about 45 angle from the hard palte
Class III: the palate turns downward sharply at about 70 angle to the hard palate.
Physiology Of Oral Cavity
Physiology Of Muscles Physiology Of Bone Saliva
Physiology Of Muscles
Physiology Of Muscles
Isotonic
Relaxation
Isometric
Physiology Of Bone
The reduction of bone may occur due to: -Anatomical factor -Prosthodontic factor (pressure
mediated resorption ) -Functional Factor -Metabolic and systemic factor:
1-Osteoporosis 2-Hyperthyroidism
Anatomical factor
Prosthodontic factor
Intensive denture wear Unstable occlusal contact Immediate denture treatment
Functional Factor
Loss of stimulation is essential in accelerating the bone resorption.
Metabolic and systemic factors:
Osteoporosis Hyperthyroidism
Saliva
Saliva is a watery substance formed in the mouth.
Human saliva comprises 99.5% mostly water, plus electrolytes, mucus, white blood cells, epithelial cells (which can be used to extract DNA), glycoproteins, enzymes, antimicrobial agents such as secretory IgA and lysozyme
Roles Of Saliva
Lubrication Digestion Role In Taste Immune Other ( In prosthodontics )
Major Salivary Glands
Parotid Submandibular Sublingual
They produce about 90 % of total salivary production.
Minor Salivary Glands
Labial, buccal and lingual mucosa
Soft palate Lateral parts of hard palate Floor of the mouth
The produce about 10 % of saliva.
Sialorrhea
Excessive production of saliva (hypersalivation).
Make impression procedure more difficult.
May occur temporarily after insertion of denture.
Xerostomia And Hyposalivation
Injury due to losing lubricant abilities of saliva.
Loss of retention
Causes Treatment
Conclusion
Thank You For Listening